It is common for shops, when closed, to have their doors and windows shielded with metal shutters to prevent theft and robbery. Generally, the upper end of such a shutter is attached to the upper part of a door or a window and the lower end can be freely rolled up or unrolled. When shops are opened, the shutters are rolled up to have the doors and windows exposed. When shops are closed, the rolled-up shutters are unrolled and have their lower ends fixed. This kind of conventional shutters is composed of a plurality of building blocks made of iron, aluminum or steel. This kind of shutters has the disadvantages of being inconvenient to manufacture, transport and install. Also, when shutters are unrolled, people can not see the articles in shop windows through the shutters; if holes are made in shutter blocks, although the articles in shop windows can be seen, rain water can easily flow in through the holes when it is raining to wet down the doors and windows of the shop.